1. Technical Field
The present invention generally relates to touch-control technologies and, particularly to a touch-control system and touch-sensing method thereof.
2. Description of the Related Art
FIG. 1 shows an isometric view of a touch-control system in prior art. Referring to FIG. 1, a touch-control system 100 is used for detecting the position of a pointer 102. The touch-control system 100 includes a panel 104, an image sensing apparatus 106, an image sensing apparatus 108 and a processing circuit 110. The touch-control system 100 further includes a reflector element 112, a reflector element 114 and a reflector element 116. A rectangular area labeled with label 18 is used as a sensing area of the touch-control system 100. The processing circuit 110 is electronically coupled to the image sensing apparatuses 106 and 108, so as to acquire the actual touch position of the pointer 102 according to the pointer images sensed by the two image sensing apparatuses. The description and the prior art recited in Taiwan patent No. 097126033 can be referred to obtain a detailed sensing theory and calculating method of the touch-control system 100. Here we will not go further on this issue.
FIG. 2 shows a schematic view of the touch-control system 100 used with single touch. In FIGS. 1 and 2, the objects of uniform labels represent one same element. In FIG. 2, the image sensing apparatus 106 can senses the pointer 102 along the sensing path 202, the image sensing apparatus 108 can senses the pointer 102 along the sensing path 204. Thus, the processing 110 only need to calculate the crossing point of the sensing paths 202 and 204, and the position of the pointer 102 can be acquired. However, when the touch-control system 100 is used with multi touch, some problems may appear. FIG. 3 is taken to explain the touch-control system 100 used with multi touch.
FIG. 3 shows a schematic view of the touch-control system 100 used with multi touch. In FIGS. 1 and 3, the objects of uniform labels represent one same element. In addition, labels 302 and 304 are both represent a pointer. In FIG. 3, the image sensing apparatus 106 can senses the pointers 302 and 304 respectively along the sensing paths 202 and 312, the image sensing apparatus 108 can senses the pointers 302 and 304 respectively along the sensing paths 204 and 314. However, due to the processing circuit 110 can acquire the positions of the pointers 302 and 304 by calculating the cross points of above sensing paths, thus, the process circuit 110 may taking the positions labeled by 306 and 308 for the positions of the pointers 302 ands 304, so that so-called ghost points are generated. Thus, the processing 110 can not accurately determine the actual touch position of the pointers 302 and 304.